Not applicable
The present invention relates to an improved synthetic surface for sports and other uses that replicates the appearance and playing conditions of natural grass, and particularly to simulate wet weather conditions and more realistic game play.
For years natural turf surfaces were used for most outdoor sports. However, natural turf (grass) surfaces do not stand up well to heavy use and poor weather conditions. Under these conditions, natural turf surfaces deteriorate rapidly and may present unsafe playing conditions. The natural grass and its root system is destroyed, leaving only bare earth as the playing surface. Additionally, natural turf surfaces do not grow well in areas that are routinely exposed to low ambient temperatures, or on fields that are used extensively or for multiple sports, as well as in partly of fully enclosed sports stadiums.
Synthetic surfaces have been used as an alternative to natural turf surfaces to overcome its disadvantages. Synthetic grass surfaces require less maintenance and can withstand a more intensive use than natural turf. Synthetic turf can be categorized into two generalized divisions, conventional turf and filled turf. Conventional synthetic turf is a dense synthetic material that has the appearance of dense grass blades, which is placed upon a foundation of asphalt, concrete, wood, or other foundation. Conventional turf provides a synthetic playing surface that closely simulates the appearance and physical characteristics of natural turf, however, there is a significant expense associated with preparing and installing an appropriate cushioning and drainage system. In order to achieve a highly durable, less expensive alterative to conventional turf, there have been numerous attempts to use top dressings or fillings between the synthetic grass blades. Filled synthetic turf is installed upon similar foundations and utilizes materials similar to conventional turf, but with greater spacing between the synthetic grass blades to accommodate the top dressing.
Filled turf surfaces have been top-dressed with sand, as shown by way of example in U.S. Pat. No. 3,995,079, and U.S. Pat. No. 4,389,435, or a mixture of sand and other particulate materials, as shown by way of example in U.S. Pat. No. 4,337,283, U.S. Pat. No. 4,396,653 and resilient particles without sand, as shown by way of example in U.S. Pat. No. 5,041,320. The particulate material provides resiliency to the synthetic surface. U.S. Pat. No. 6,299,959, which is herein incorporated by reference, discloses a particularly useful filled turf surface comprising a xe2x80x9cthatch zonexe2x80x9d layer of tufted nylon 6.6 that locks the resilient particles inside the xe2x80x9cthatch zone.xe2x80x9d
Filled turf surfaces have several disadvantages. Filled turf surfaces that utilize sand or a mixture of a significant amount of sand and other particulate material exhibit the tendency to compact over time. With an increase in compaction, the surface becomes progressively harder and less resilient. Replacing, or even loosening the compacted material can be expensive and adds to the costs of maintaining the surface. Compaction also inhibits drainage of water from the surface.
Other aspects of game play are also affected when filled turf surfaces are utilized. The level of resiliency and compaction can affect the way a ball responds to the surface, as well as the increase in traction of the game players footing. Additionally, the elements of wet weather game play, such as the reality of soiled clothing and the changes in game play associated with wet weather conditions, are not present, particularly in indoor installations.
In order to improve conventional synthetic sports playing surfaces and provide more realistic game play, a synthetic sports playing surface is provided comprising, generally, a synthetic grass having grass-like fibers secured to a backing fabric. The backing fabric may be a single layer or multiple layers. Further, the backing fabric may be constructed as a laminate of woven and non-woven layers, multiple woven layers or multiple non-woven layers. Preferably, the backing fabric is a laminate of a woven fabric component and a fiberglass reinforcing matrix. Most preferably, the backing fabric comprises a fiberglass reinforcing matrix integrated with a woven fabric component, such as the composite fabric disclosed in pending patent application Serial No. (not yet assigned), filed Oct. 16, 2002, which said disclosure is herein incorporated by reference. The grass-like fibers can be formed of any polyolefin or their co-polymers, but are preferably polyethylene co-polymer because it is less abrasive. The grass-like fibers may be constructed as a monofilament yarn or may be constructed as a slit film type yarn. The tips of the grass-like fibers can be mechanically fibrillated either during of subsequent to installation of the top dressing to give the grass-like surface a denser appearance and to help contain the top dressing. The grass-like fibers can be secured to the backing by numerous means including knitting or weaving, however, tufting is the preferred means. After securing the grass-like fibers to the backing fabric, the backing fabric is sprayed with a resilient latex type or other carpet adhesive to lock in the secured fibers. The top dressing comprises natural soil or a synthetic soil or may be a mix of natural soil or synthetic soil with conventional infill material, such as resilient particles, mineral particles coated with a resilient layer or other types of infill materials. The filled fabric generally described above may be installed over a drainage system and can have an irrigation system, particularly for an indoor field, in order to simulate wet weather conditions, provide for more realistic game play and manage other aspects of the field.